Industrial truck with self actuated load lifting attachment



June 2, 1970 E. s. ESSER 3,515,299

INDUSTRIAL TRUCK WITH SELF-ACTUATED LOAD LIFTING' ATTACHMENT Filed July22, 1968 INVENTOR.

ERNST S ESSER ATTORNEY.

United States Patent U.S. Cl. 214-350 9 Claims ABSTRACT OF THEDISCLOSURE An industrial truck for transporting dies or the like,equipped with a cam that is moved by a die as the die moves endwisetoward the truck. A surface of the cam contacts an undersurface of thedie for lifting the die as the cam is moved by the die. Therefore, thecam is selfactuated for lifting the die.

This invention relates to an industrial truck, and more particularly anindustrial truck of that type adapted to transport heavy dies.

Industrial lift trucks designed for the handling of heavy dies are wellknown in the art. In general, a truck of the particular class has arelatively low platform of considerable area. While the platform isrelatively low, it is generally positioned above the level of a die thatis to be moved. Since a die may weigh 20,000-60,000 pounds, it isreadily understandable that the lifting of the die from a relatively lowposition to the level of the platform of the industrial truck, presentsa considerable problem because of low press bed height.

In one form of industrial truck manufactured by the assignee of thisapplication, Eaton Yale & Towne Inc., power actuated level mechanism ismounted at one end of the frame of the truck immediately below theplatform. The lever mechanism includes lifting levers equipped withrollers that are adapted to move under a die that is to be loaded on theplatform of the truck, and rams are provided for swinging the levers soas to move the rollers upwardly, bringing the die to the level of theplatform.

In a construction of this class, it is obvious that the area and lengthof the load platform of the industrial truck is naturally decreased tothe degree necessary for the mounting of the levers, since the leversmust project beyond the load accepting surface of the platform. Also, ofcourse, means must be provided for supplying hydraulic fluid to therams, to mount the rams on the truck, and to control the rams. In such ahydraulic system, horizontal movement of the die has to be coordinatedwith lifting of die, otherwise the die can slip from the lift-roller.

It must also be considered that while the prior art construction I haveoutlined will operate effectively to lift a die so that it may be movedonto the plateform of a truck, additional means must be provided for somoving the die onto the platform. These means may take the place of acable actuated by a winch, or may also take the form of fingers movablein grooves formed in the surface of the platform of the trucks. In priorart trucks, such fingers are utilized for manipulating a die, and formoving a die off a truck platform for deposit on a machine, etc. Fingersof the particular class are also frequently used for actuating a cablefor moving a die, all as is well known to those skilled in this art.

The invention that I have conceived and which I describe in thisapplication, utilizes what I term a cam mechanism mounted on a truck andactuated merely through movement of the die toward the truck platform,for actually lifting the die so that it may be deposited 'ice on thesurface of the truck platform. As a feature of the invention, I utilizea cam having at least two arms, one arm to be applied under the die,while another arm is contacted by an end surface of the die. Movement ofthe die against the cam contacted by its end surface, will bring aboutrotation of the cam on its mounting means, and the surface that is underthe die will lift the die. In other words, the mechanism isself-actuated by the pushing or pulling of the die relatively to thetruck. Since in the old form of mechanism eariler discussed and wellknown in the art, it is necessary also to pull or push the dierelatively to the truck, it is obvious that I eliminate in myconstruction, an entire relatively costly power operating mechanism,While yet achieving all of the results inherent in the mechanism of theprior art.

As a particular feature of my invention, I prefer to use a cam having apair of crossed arms, the cam being rotatably mounted in a horizontalaxis where the arms meet and cross. The ends of the crossed arms areequipped with rollers for contacting the end surface of the load andalso the undersurface of the load.

As a particular feature of my invention, the cam is adapted to becontrolled by mechanism-that may take the form of a brake or a lockingpin inserted so as to prevent rotation. When the brake or other means islocked so as to hold the cam in a particular position, one surface ofthe cam positioned beyond the normal extent of the platform, forms anefiective extension of the platform. Therefore, through my invention,the effective length of the platform is considerably longer than theeffective length of the platform of prior art trucks of this type, eventhrough I eliminate the power mechanism and other parts of the priorart. Therefore, it will be appreciated that I achieve an extraordinarilyvaluable result while still eliminating mechanism that is essential inprior art constructions.

As a still further feature of the invention inherent in theconstruction, the brake mechanism to which I have alluded, may beutilized to control the speed of rotation of the cam. Therefore, the cammay be utilized effectively to permit removal of a heavy die since, asthe die strikes the cam, the cam may be rotated very slowly so as inturn to lower the die very slowly to a lowered position. Therefore, I amable to achieve the results of the prior art without the requirement ofthe power mechanism of the prior art. While this last feature of myconcept may be achieved through controlling the die movement by a cable,those skilled in the art will appreciate that it is almost impossible topay out a cable at the slow rate necessary to lower a die. Utilizing myinvention, it is possible to control and move the cam in extremely smallincrements to lower a die most effectively.

I have thus outlined rather broadly the more important features of myinvention in order that the detailed description thereof that followsmay be better understood, and in order that my contribution to the artmay be better appreciated. There are, of course, additional features ofmy invention that will be described hereinafter and which will form thesubject of the claims appended hereto. Those skilled in the art willappreciate that the conception on which my disclosure is based mayreadily be utilized as a basis for the designing of other structures forcarrying out the several purposes of my invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions as do not depart from the spirit and scope of myinvention, in order to prevent the appropriation of my invention bythose skilled in the art.

Referring now to the drawings, FIG. 1 is an elevation of a typical truckto which my invention may be applied. FIG. 2 is a plan view of that endof the truck of FIG. 1

3 on which is mounted the cam of my invention. FIG. 3 is a view similarto FIG. 1 showing the die as it first contacts the cam, and illustratinghow the cam forms an extension, in effect, of the platform of the truckwith the die supported thereby. FIG. 4 illustrates a modified form ofthe invention.

Referring now more particularly to the drawings, reference numeralindicates generally an industrial truck of the class to which myinvention may be applied. The truck is adapted to move over a floor orground surface on Wheels 11 and 12. The operator stands on a platform at'13 and controls the movement of the truck through suitable controlsthat are not shown, and steers through a steering wheel 14. Wheels 11are the traction wheels, and they are driven by an electric motor or byan internal combustion engine. In the truck illustrated, the wheels 11are driven by an electric motor powered by a battery housed in thecasing 24.

The cam of my invention, in its preferred form, is well illustrated inFIGS. 1, 2 and 3. Because of the size of the truck and the loads to behandled, I actually use three identical cams, each of which isdesignated generally by reference numeral 15. Each cam is preferablyfabricated from a heavy casting in the form of crossed arms. Thus, oneof the arms is designated by reference numeral 16, and the other arm byreference numeral 17. Where the arms cross one another, there is a borefor housing a shaft 18. The shaft 18 is itself adapted for rotation infour longitudinally positioned plates 19, 20, 21 and 22 integral withthe truck main frame. In that form of my invention in which a brake isused for controlling the rotation of the three earns 15, each of thecams is preferably keyed to the shaft 18 at 23 so that, the three camsrotate together with the shaft 18, and are controlled as will beindicated presently.

For contacting a die D or similar load, each of the arms 16, 17 has atits opposed ends a freely rotating roller, the roller on the upper endof the arm 16 in FIG. 3 being designated by reference numeral 25, whilethe lower roller on the end of the arm 17 is designated by referencenumeral 26. In the position of the cam shown in FIGS. 1-3, the roller 26is the lifting roller, while the roller 25 is the roller that is pushedby movement of the die I), all was will be explained presently.

At one end of the shaft 18, as well seen in FIG. 2, a brake 30 isprovided for braking the shaft 18 and for locking it in a particularrotated position. The brake is shown controlled by a rod 31, but thebrake may be a hydraulic brake, and in that event, reference numeral 31indicates conventional tubing for transmitting fluid under pressure tothe brake 30. In any event, through the utilization of a standard formof braking mechanism, the shaft 18 may be held against rotation, orcontrolled in its rotation so that it will rotate very slowly, movingwith it the three cams 15. In describing the invention, I shall refer tobut the one cam 11 shown in FIGS. 1 and 3.

Obviously, if the cam illustrated in FIG. 3 is held locked, the roller25 will lie at the level of the upper surface 35 of the platform of thetruck, forming an effective extension of the platform. While there willbe some slight space between the end of the platform and the roller 25,this space will not be of consequence, and the roller 25 may be utilizedto support a load just as effectively as were the load platform surface35 continued to the roller 25.

In FIG. 3 a die D is shown in contact with the roller 25 but not withthe roller 26. This contact is brought about generally through movementof the truck against the die. Let us now assume that the die is pulledtoward the truck. This movement of the die may take place in severalways. Thus, in FIG. 1 the truck is shown equipped with a winch W adaptedto wind a cable 36. This cable 36 may be utilized to pull the die Dtoward the truck in a manner well known by those skilled in the art. Onthe other hand, the die may be moved forwardly relatively to the truckby movement of the truck in the direction of the arrow 37 in FIG. 3 asthe die is held against movement.

In any event, with the die supported on skids or dunnage 38 below thelevel of surface 35 of the truck platform, any movement of the dietoward the truck, will cause the roller 26 to move to its position ofFIG. 1 where it is directly under the die D. Obviously, continuedrotation of the roller 25 and the arm 16 in a counterclockwise directionin FIG. 1 will cause the roller 26 to exert continued upward pressureagainst the bottom surface of the end of the die and to lift that end ofthe die upwardly and away from the skid 38. In FIG. 1 it will be notedthat roller 25 has its upper surface somewhat above the upper surface 35of the platform of the truck. Obviously the roller 26 will also reachthe position of the roller 25 while lying under the bottom of the die.Therefore, the end surface of the die will actually reach a positionjust above the surface 35 of the truck prior to moving to its finalresting position of FIG. 3 shown in dash and dotted lines where theroller 26 will lie in the position of the roller 25, and will form aneffective extension of the upper surface 35 of the platform. The roller26 may be held with cam 15 in this position by such means as brake 30.

In my truck, I may utilize die actuating fingers such as shown byreference numeral 50, which ride in grooves 51 formed in the platformsurface 35. Such die handling fingers are well known in the art, and maybe used to move cables such as the cable 36, or to physically contact adie to push it off the load or to swing it on the surface 35.

It will be quite obvious that a reverse movement of the cam 15 isnecessary to bring about a lowering of the end of a die from surface 35.In that event, the particular roller 25 or 26 lying under the die willprevent its swift movement downwardly, if that roller is prevented fromswift movement by the utilization of the brake 30. Therefore, byapplying the brake 30, very slow rotation of the cam 15 in a loweringdirection, is made possible.

In FIG. 4 I show a simplified form of cam mechanism designated generallyby reference numeral 60 and comprising a generally L-shaped memberhaving a lift surface at 61 and a push surface at 62, the cam beingmounted on the shaft 18 where the two arms, in effect, of the cam 60cross. Essentially, cam 60 will operate as does cam 15.

It is to be understood that the generally L-shaped cam 60, whileoperating very well in accordance with the principles of my invention,may require initial positioning or repositioning prior to lifting orlowering a die. That is, it is necessary for the legs of the L to beappropriately positioned with respect to the die. Whereas, a cammechanism having three or more legs generally symmetrically spaced abouta central axis will automatically assume the proper position for liftingor lowering a die as required.

I do believe that the very considerable contribution of my inventionwill now be understood by those skilled in the art.

I claim:

1. In an industrial truck, a main frame having a load platform formedwith a surface for receiving a load, a lifting cam, means mounting saidlifting cam for pre determined movement on said main frame, a liftroller and a push roller rotatably mounted on said cam and bothprojecting outwardly relatively to one edge of said platform in oneposition of said cam whereby said lift roller may be applied under theend of a load as said push roller is applied against a surface of saidload facing said push roller, whereby the application of force to movesaid load relative to said platform will, through the push roller onsaid cam, move said cam so that the lift roller will lift the loadrelatively to the main frame and the platform.

2. In the combination of claim 1, the feature that the cam is pivotedrelatively to the main frame on a horizontal axis below the surface ofthe platform on which the load is to be deposited.

3. In the combination of claim 1, the feature that at least part of thecam is in the form of an L-shaped lever with said rollers located at theends of the arms forming the L, the lever being pivoted to the platformat the juncture of the arms.

4. In the combination of claim 1, the feature that the cam is in theform of a plurality of intersecting arms rotatably mounted on the mainframe where the arms intersect, and said rollers are on the ends of saidarms.

5. In the combination of claim 1, means for controlling the speed ofmovement of the cam under pressure of a load to facilitate use of thecam lift roller for lowering slowly the end of a load.

6. In the combination of claim 1, means for holding said cam at aposition thereof in which a surface of said cam lies at the level of theload receiving roller surface of the platform to form, in effect, a partof the load receiving surface of the platform.

7. In an industrial truck, a main frame having a load platform formedwith a surface for receiving a load, a lifting cam mounted on said framefor rotation about an axis located below said load receiving surface,said lifting cam comprising a lift surface for engaging one face of theload and a push surface for engaging another face of the load, said liftsurface being located below said axis and said push surface beinglocated above said axis when said cam is in an initial load engagingposition, said lift and push surfaces being radially spaced from saidaxis and having an angularly spaced relationship to one another wherebya force exerted by the load on said push surface will create a momentabout said axis and cause said lift surface to raise said load to aposition approximate the load receiving surface.

8. In the combination of claim 7, means for controlling the speed ofmovement of the cam under a load to facilitate use of the cam liftsurface for lowering slowly the end of a load being moved relatively tosaid platform.

9. In the combination of claim 7, said cam further comprising aplurality of intersecting arms with said axis at the intersection ofsaid arms and a shaft passing along said axis and rotatably mounted withrespect to said load platform, said push and said lift surfacescomprising rollers rotatably mounted at the ends of said arms andincluding means for controlling the speed of cam movement comprisingmeans locking said cam to said shaft and a brake mounted on said shaftto allow retardation of rotation of said shaft under load.

References Cited UNITED STATES PATENTS 1,139,243 5/1915 Warner 1878.492,492,364 12/1949 Levy 214-354 2,541,523 2/1951 Lang.

ALBERT J. MAKAY, Primary Examiner U.S. Cl. X.R. 214-84; 2542

